1. Field of the Invention (Technical Field)
The present invention relates to bioactive films, particularly film dressings for treatment of wounds, lesions and the like, which films include one or more bioactive molecules or medically useful substances bound to a hydrophobic group-containing polyanionic coating on the film.
2. Background Art
Treatment of various lesions, including ulcers, wounds and the like, is a medical challenge. Particularly in patients with compromised immune systems or disorders such as diabetes, ulcers, or sores, wounds and the like are extremely difficult to heal. It has been recognized that certain compounds that are locally delivered, such as cytokines, various drugs and the like, can aid in wound healing. However, there is no wound dressing or film which is effective in delivering these compounds over clinically relevant times. There are also no biodegradable wound dressings which, when applied to an internal injury such as to an organ or bone, deliver compounds over clinically relevant times.
It has previously been shown that various compounds useful for wound healing can bind to a number of different substrates. For example, growth factors can bind to polymer matrices and be later released. Growth factors combined with “matrix material” such as alginates, heparin, and so on, can bind to a paste which is useful for wound healing. Chitosan with an attached polysaccharide such as heparin, can also be used to make a film that is useful for wound healing.
Wound dressings that contain a drug useful for wound healing are known in the art. For example, the use of protease inhibitors in wound dressings has previously been shown. The peptide may either be attached directly to the dressing material or to a matrix. Another dressing for wounds uses corpuscles of a water-insoluble matrix that contains biologically active compounds. The corpuscles are attached to the wound dressing. However, there is no disclosure wherein these wound dressings allow for modulation of release of the compound. Finally, the use of cytokines and growth factors that bind to heparin and can be used on bandages has been shown. However, there is no disclosure of heparin binding to the bandage substrate, or modulation of release therefrom.
Use of coatings incorporating siloxanes is also known in the art, as is disclosed in U.S. Pat. No. 6,342,591, entitled Amphipathic Coating For Modulating Cellular Adhesion Composition and Methods, to Paul O. Zamora, Shigemasa Osaki and Ray Tsang; U.S. Pat. No. 5,955,588, entitled Non-Thrombogenic Coating Compositions and Methods for Using Same, to Ray Tsang and Shigemasa Osaki; and international patent application PCT/US01/24000, entitled Bioactive Coating Compositions and Methods, to Paul O. Zamora, Shigemasa Osaki and Ray Tsang. The specification of each of the foregoing is incorporated herein by reference.
There is thus a need for localized delivery of drugs, including biomolecules, for use in treatment of ulcers, sores, wounds and the like. For many conditions there is a need for controlled or sustained release over a period of time, such that the drug may be continuously delivered.